Pump



June 21, 1960 R. J. DAL'roN 2,941,477

PUMP

Filed llarch 16, 1959 INVENToR. ROBERT J. DALTON BY 'l MRM ATTDRNEY United States Patent O PUMP Robert J. Dalton, Hadoniiuld, NJ., assignor to Arthur H. Thomas Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Mar. 16, 1959, Ser. No. '799,740

15 Claims. (Cl. 10B-87) The present invention relates to a pump, and more particularly to a magnetically driven pump.

In the pumping of corrosive material, it is necessary to use a pump which is not adversely affected by the corrosive material. In such a pump, not only does the pump have to be made of a material which will not-be attacked by the corrosive material, but the means for sealing the interior of the pump must also be able to withstand the corrosive material. The seal of a conventional pump which is most subject to be attacked by the material being pumped is the seal between the drive shaft for the pump and the pump casing where the drive shaft passes through the wall of the casing. Therefore, in the pumping of corrosive material,it is desirable to have a pump in which the drive means for the pump does not pass through the pump casing so as to eliminate any openings in the pump casing which must be sealed.

Similar problems arise in the pumping of materials which must be protected from being contaminated. Not only does the pump have to be made of a material which will not contaminate the material being pumped, but the pump must also be sealed to prevent any contaminations from the air from entering the pump.

It is an object of the present invention to provide a novel pump.

It is another object of the present invention to provide a pump for pumping corrosive materials or materials which must be protected from contamination.v

It is still another object of the present invention to provide a magnetically driven pump.

. lt is a further object of the present invention to provide apump having a magnetic drive which will not be disrupted when a load is placed on the pump.

Other objects will appear hereinafter.

For the purpose of illustrating the invention there is shown in the drawings a form which is presently preferred; it being understood, however, that this-invention is not limited to the precise arrangements and instrumentalities shown.

Figure l is a sectional view, partly in elevation, of the pump of the present invention.

Figure 2 is a top elevational view, partly sectioned, of the magnetic drive of the pump of the present invention.

Figure 3 is a sectional view taken along line 3--3 of Figure 1.

Figure 4 is a sectional view taken along line 4-4 of Figure 1.

Referring to Figure l initially, the pump of the present invention is generally designated as 10. Pump comprises a casing, generally designated as 12, an impeller 14, and a magnetic drive, generally designated at 16.

Casing 12 comprises a cylindrical outer wall 18, a circular back plate 20 secured to one end of the outer wall 18, and a circular front plate 22 secured to the other end of the outer wall 18. Outer wall 18, back wall 20, and front wall 22 are all made of a plastic, and are either heat fused together or secured together by a suit- 2,941,477 Patented June 21, 1960 rice able cement. Outer wall 18 has a tubular outlet port 24 extending substantially tangentially therefrom (see Figure 4). .Back plate 20 is larger in diameter than the outer wall 18, and has. four circumferentially spaced holes 26 therethrough adjacent the outer periphery of the back plate 20. Back plate 20 has a cylindrical recess 28 in the center of its inner surface. Front plate 22 also'has acylindrical recess 30 in the center of its inner surface, which is in alignment with the recess 28 in the back plate 20. Front plate 22 has a plurality of inlet holes 32 therethrough adjacent to but spaced from the recess 30. An inlet tube 34 is secured to the outer surface of the front plate 22, and surrounds the inlet holes 32 in the front plate 22. Inlet tube 34 is also made of a plastic, and is heat fused or cemented to the front plate 22. Thus, the entire casing 12 is made of a plastic material which will not be attacked by the material being pumped,

and which will not contaminate the material being,

pumped. Also, except for the inlet holes 32 and the outlet port 24, the casing 12 has no openings into the interior of the casing 12 through which the material being pumped can leak out, or through which contaminants may enter the casing 12.

Impeller 14 comprises a rectangular block of a plastic material which will not be attacked by and which will not contaminate the material being pumped. Impeller 14 has a pair of parallel, cylindrical recesses 36 extending therethrough from one end of the impeller 14. A separate permanent bar magnet 38a and 38b is within each of the recesses 36. Magnets 38a and 38b are arranged with their north poles being juxtaposed adjacent one end of the impeller 14, and their south poles being juxtaposed adjacent the other end of the impeller 14. Plastic plugs 40 are secured in the open ends of the recesses 36 to seal the magnets 38a and 38h within the impeller 14. A trunnion 42 is secured in a recess 44 in the center of one face of the impeller 14. A trunnion 46 is secured in a recess 48 in the center of the other face of the impeller 14. Trunnions 42 and 46 are in direct alignment, and project beyond the faces of the impeller 14. Trunnion 42 is rotatably supported in the recess 28 in the back Wall 20 of casing 12. Trunnion 46 is rotatably supported in the recess in the front wall 22 of the casing -r an electric motor 52. Rods 50 have threaded outer ends which extend through the holes 26 in the back plate 20 of the casing 12. A pair of nuts 52 are threaded on the end of each of the rods 50 at opposite sides of the back plate 20 to secure the casing 12 on the rods 50. The casing 12 is mounted on the rods 50 with the axis of rotation of the impeller 14 being in direct alignment with the longitudinal axis of the motor shaft 54. The magnetic drive 16 is mounted on the end of the motor shaft 54 adjacent the outer side of the back plate 20 ofthe casing 12.

Magnetic drive 16 comprises rectangular block 56 of a non-magnetic metal, such as brass. central hole 58 extending from face to face thereof through which motor shaft 54 extends. A setscrew 60 is threaded through the block 56 and engages the motor Block 56 has ahole 58, and are perpendicular to the hole 58. Slots 64 extend from the ends of the block 56 to the holes 62 to permit expansion of the holes 62. Permanent bar magnets 66a and 66b extend through the holes 62, and project beyond the sides of the block 56. Setscrews 68 are threaded through the block 56 and engage the magnets 66a and 66b to secure the magnets 66a and 66b in the block 56. Magnets 66a and 66b are arranged with their north poles being juxtaposed, and their south poles being juxtaposed. Magnets 66a and 66b extend parallel to the impeller magnets 38a and 38b with the north poles of the magnets 66a and 66b being juxtaposed to the south poles of the magnets 38a and 38b. Magnets 66a and 66b are spaced apart a distance greater than the spacing between the impeller magnets 38a and 38b for reasons which will be explained below. However, if desired, the impeller magnets 38a and 38b can be spaced apart a distance greater than the spacing between the drive magnets 66a and 66b.

The operation of the pump of the present invention is as follows:

Electric motor 52 is turned on to rotate the magnetic drive 16 in the direction of arrow 70 in Figure 2. Since the poles of the drive magnets 66a and 66b are juxatposed to the opposite poles of the impeller magnets 38a and 38h, the impeller magnets 38a and 38h are magnetically coupled to the drive magnets 66a and 66b. Thus, when the magnetic drive 16 is rotated, the impeller magnets 38a and 38h will lfollow the drive magnets 66a and 66b, and thereby rotate the impeller 14. As the impeller 14 rotates, the sides of the impeller 14 engage the ud medium fed into the casing 12 through the inlet tube 34 and inlet holes 32, and forces the uid medium radially outwardly to the outlet port 24.

As the impeller 14 begins to rotate, the load applied to the impeller 14 by the fluid medium being pumped tends to slow down the rotation of the impeller 14, and thereby tends to drag the poles of the impeller magnets 38a and 38b out of the phase with the poles of the drive magnets 66a and 66b. If the magnetic drive and the impeller each included only one magnet, the magnetic circuit between the magnets would be lengthened when the load on the impeller slowed down the impeller. The lengthening of the magnetic circuit between the magnets would decrease the magnetic coupling between the magnets, and the impeller would continue to slow down until it stopped completely. However, in the pump 10 of the present invention, since the impeller magnets 38a and 38b are 4 1. A pump comprising an enclosed plastic casing having an inlet opening and an outlet opening, a plastic impeller rotatably supported within said casing, a pair of permanent magnets imbedded in said impeller, said magnets being parallel to each other and extending transversely to and along opposite sides of the axis of rotation of said impeller, and a magnetic drive including a pair of parallel drive magnets, said magnetic drive being adapted to be mounted adjacent a wall of said casing for rotation of said drive magnets about the axis of rotation of said impeller and with the drive magnets substantially parallel to the impeller magnets.A

2. A pump in accordance with claim 1 in which the magnets of one of the pair of magnets are spaced apart a distance greater than the distance between the other pair of magnets.

3. A pump in accordance with claim 2 in which the drive magnets are spaced apart a distance greater than the distance between the impeller magnets. v

4. A pump comprising an enclosed plastic casing, said casing including a cylindrical outer wall having an outlet opening therethrough, a back wall secured across one end of the outer wall, and a front wall secured across drive including a pair of parallel drive magnets, said 'i magnetic drive being' adapted to be mounted adjacent the back wall of said casing for rotation about the axis of rotation of said impeller with the drive magnets substantially parallel to the impeller magnets. v

5. A pump in accordance with claim 4 in which the impeller includes a pair of aligned trunnions secured to and extending from opposite sides of lsaid impeller, said closer together than the spacing between the drive magnets 66a and 66b, when the impeller 14 is slowed down by the load of the uid medium being pumped, one'pole of the impeller magnet 3817 will move closer to the corresponding pole of the drive magnet 66b, and thereby shorten the magnetic circuit between the corresponding poles of the impeller magnet 381 and drive magnet 66b. At the same time, the corresponding pole of the impeller magnet 38a is moved to a position intermediate the corresponding poles of the drive magnets 66a and 66b. The impeller magnet 38a will then be magnetically coupled'to both the drive magnet 66a and 66b. Thus, there will be provided a three-way magnetic circuit between the impeller magnets 38a and 38h and the drive magnets 66a and 66b which will prevent further slowing down of the rotation of the impeller 14 so that the impeller 14 will continue to rotate with the magnetic drive 16. Thus, the pump l0 of the present invention is provided with a magnetic drive which will not be disrupted when a load is applied to the impeller 14 of the pump 1-0.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

I claim:

trunnions being rotatably supported in recesses in the` inner surfaces of the back and front; walls of the casing. 6. A pump in accordance with claim 5 in which the impeller is a rectangular block of plastic, the trunnions are secured in aligned recesses in the center of the faces of the block, and the impeller magnets are enclosed in parallel recesses in the block.

7. A pump in accordance with claim 4 in which the magnets of one of the pair of magnets are spaced apart a distance greater than the distance between the other pair of magnets.

48. A pump in accordance with claim 7 in which the drive magnets are spaced apart a distance greater than the distance between the impeller magnets.

9. A pump in accordance with claim 4 in which the magnetic drive comprises a block of non-magnetic material having a central hole therethrough for receiving a drive shaft, and a pair of parallel holes therethrough on opposite sides of and perpendicular to said central hole, and the drive magnets are secured in saidl parallel holes and project beyond the sides ofvsaid block.

10. A pump comprising an enclosed plastic casing, said casing including a cylindrical outer wall having an outlet opening therethrough, a back wall secured across one end of the outer wall, and a front wall secured across the other end of said outer wall, said front wall having an inlet opening therethrough, a plastic impeller within ,said casing and rotatably supported between said back wall and front wall, a pair of permanent magnets imbedded in said impeller, said magnets being parallel to each other and extending transversely to and along opposite sides of the axis of rotation of said impeller, means mounting said casing on a motor with the axis of rotation of said impeller being in alignment with the `axis of the drive shaft of the motor, and a magnetic drive mounted on the drive shaft of the motor adjacent the back wall of the casing, said magnetic drive including a pair of drive magnets extending perpendicular to said drive shaft and para1- lel to said impeller magnets.

11. A pump in accordance with claim 10 in which the back wall of the casing is larger in diameter than the outer wall of the casing, and the back wall has a plurality of circumierentially spaced holes therethrough adjacent the outer periphery thereof, and the means mounting the casing on the motor comprises a plurality of rods extending from the motor and through the holes in the back wall, and nuts threaded on said rods and engaging said back wall of the casing to secure said casing on said rods. 12. A pump in accordance with claim 10 in which the impeller includes a pair of aligned trunnions secured to and extending from oppositel sides of said irnpeller, said trunnions beingrotatably supported in recesses in the inner surfaces of the back and front walls of the casing.

13. A pump in accordance with claim 10 in which the magnets of one of the pair otI magnets are Aspaced apart a distance greater than the distance between the other pair of magnets.

14.` A pump in accordance with claim 13 in which the drive magnets are spaced apart a distance greater than the distance between the impeller magnets.

15. A pump in accordance with claim l() in which the magnetic drive comprises a block of non-magnetic material having a central hole therethrough in which the drive shaft of the motor is secured, and a pair of parallel holes therethrough on opposite sides of and perpendicular to said central hole, and the drive magnets are secured in said parallel holes and project beyond the sides of said block.

References Cited in the file of this patent UNITED STATES PATENTS 2,350,534 Rosinger I-une 6, 1944 2,481,172 Staggs Sept. 6, 1949 2,669,668 Okulitch et al Feb. 16, 1954 2,810,349 Zozulin Oct. 22, 1957 

